Representation of canopy snow interception,unloading and melt in a parsimonious snowmelt model

Recent improvements in the Utah Energy Balance (UEB) snowmelt model are focused on snow–vegetation–atmosphere interactions to understand how different types of vegetation affect snow processes in the mountains of Western USA. This work presents field work carried out in the Rocky Mountains of Northern Utah to evaluate new UEB model algorithms that represent the processes of canopy snow interception, sublimation, mass unloading and melt. Four years' continuous field observations showed generally smaller accumulations of snow beneath the forest canopies in comparison with open (sage and grass) areas, a difference that is attributed to interception and subsequent sublimation and redistribution of intercepted snow by wind, much of it into surrounding open areas. Accumulations beneath the denser forest (conifer) canopies were found to be less than the accumulation beneath the less dense forest (deciduous) canopies. The model was able to represent the accumulation of snow water equivalent in the open and beneath the deciduous forest quite well but without accounting for redistribution tended to overestimate the snow water equivalent beneath the conifer forest. Evidence of redistribution of the intercepted snow from the dense forest (i.e. conifer forest) to the adjacent area was inferred from observations. Including a simple representation of redistribution in the model gave satisfactory prediction of snow water equivalent beneath the coniferous forest. The simulated values of interception, sublimation and unloading were also compared with previous studies and found in agreement. Copyright © 2013 John Wiley & Sons, Ltd.     

Shear wave velocity structure beneath the Archaean granites around Hyderabad, inferred from receiver function analysis

Broadband receiver functions abstracted from teleseismicP waveforms recorded by a 3-component Streckeisen seismograph at Hyderabad, have been inverted to constrain the shear velocity structure of the underlying crust. Receiver functions obtained from the Hyderabad records of both shallow and intermediate focus earthquakes lying in different station-event azimuths, show a remarkable coherence in arrival times and shapes of the significant shear wave phases:Ps, PpPs, PsPs/PpSs, indicating horizontal stratification within the limits of resolution. This is also supported by the relatively small observed amplitudes of the tangential component receiver functions which are less than 10% of the corresponding radial component. Results of several hundred inversions of stacked receiver functions from closely clustered events (within 2°), show that the crust beneath the Hyderabad granites has a thickness of 36 ± 1 km, consisting of a 10 km thick top layer in which shear wave velocity is 3.54 ± 0.07 km/sec, underlain by a 26 ± 1 km thick lower crust in which the shear wave velocity varies uniformly with a small gradient of 0.02 km/sec/km. The shear wave velocity at its base is 4.1 ± 0.05 km/sec, just above the moho transition zone which is constrained to be less than 4 km thick, overlying a 4.74 ±0.1 km/sec half space.     

Hydro-morphometrical analyses of sub-himalyan region in relation to small hydro-electric power

The choice of site for small hydropower potentials in the inaccessible tracts of Himalayan region is a difficult task by the conventional methods. Present work suggests a site for developing a multipurpose small reservoir under GIS framework, in the Sub Himalayan region, India. Scarcity of geographical, climate and statistical data was the main problem for development of seasonal precipitation and runoff modeling for assessing water potentials and identification of possible small-scale hydropower sites. Small hydropower potential is mainly regulated by head and its durability available at site depending upon capacity of the watershed, underlying the reservoir, to produce the runoff. The study reveals that the Bari-Ka- Khad watershed (BKW) can be considered as a suitable site of interest for small-scale hydropower installation. It is having maximum drainage density (7.45 km/km²) and maximum available relief ratio (0.12), which demonstrates better capacity to produce runoff. According to drainage texture of BKW (R_t?=?2.35), it come under coarse texture and higher values of Rho coefficient (ρ?=?3.65), suggesting higher hydrologic storage during rainfall and attenuation of effects of erosion during elevated discharge.     

Ultra-low-frequency (ULF) and total electron content (TEC) anomalies observed at Agra and their association with regional earthquakes

Employing a three-component search coil magnetometer (f = 0.01–30 Hz) the ultra-low-frequency (ULF) magnetic field observations have been taken in a noise free rural site at Bichpuri, Agra, India since 20 April 2007. We have analysed 7 months of night time data from 01 May to 30 November 2007. The data show seven occurrences of ULF bursts with periods ranging from a few minutes to an hour in a wide frequency range up to 15 Hz. The occurrence of such ULF bursts has been statistically analysed. The polarization parameter analysis shows that two of these bursts occurred from sources in the ionosphere and magnetosphere (Z/X < 1). It is further seen that four bursts correlated very well with some regional earthquakes (M > 4.5), which occurred at distances less than 628 km from the observation site at Agra. In some cases the bursts occurred 1–3 days prior to the main shocks.Since earthquakes are also known to perturb the ionosphere, we have analysed total electron content (TEC) data obtained from a GPS receiver stationed at Agra since June 2006. Analysis of the data for the same period as the magnetic field observations shows that there existed TEC anomalies on all the days when ULF bursts occurred. The TEC anomalies show enhancement and depletion in the data in all cases. While the mechanisms of the ULF and TEC anomalies are not well known, it is expected that the ULF bursts occurred due to microfracturing of the earth's crust during stress accumulation and that the TEC anomalies occurred as a result of the electric field induced in the ionosphere during such processes.     

A discrete element study on the deformation and degradation of coal-fouled ballast

Acta Geotechnica - This paper presents the results of Discrete Element Modelling (DEM) which quantitively examine the effect of coal fouling on the deformation and degradation of ballast upon...     

Charged Particle Monitor on the Astrosat Mission

Charged Particle Monitor (CPM) on-board the Astrosat satellite is an instrument designed to detect the flux of charged particles at the satellite location. A Cesium Iodide Thallium (CsI(Tl)) crystal is used with a Kapton window to detect protons with energies greater than 1 MeV. The ground calibration of CPM was done using gamma-rays from radioactive sources and protons from particle accelerators. Based on the ground calibration results, energy deposition above 1 MeV are accepted and particle counts are recorded. It is found that CPM counts are steady and the signal for the onset and exit of South Atlantic Anomaly (SAA) region are generated in a very reliable and stable manner.